Title: Chromic-phosphoric acid coated aluminized steel

Abstract: Low temperature aluminum diffusion is of better quality when effected with a pack energized by aluminum chloride or other material that does not generate nitrogen and is shielded from contacting the work pieces until after the pack is heated to energizing temperatures. The resulting aluminizing very effectively protects steels against corrosion in marine atmospheres, particularly when there is a chromate-type coating applied over the aluminizing. Highly effective chromate-type coating mixture consists essentially of aqueous solution of chromic and phosphoric acid also containing magnesium salts of said acids with or without dispersed polytetrafluoroethylene particles. The salts of divalent metals such as calcium, zinc, strontium, manganese, cobalt and nickel whose chromates are soluble in acid, can be used instead of or in addition to the magnesium. Such coating mixture is best applied over porous pre-coating of colloidal inert particles.

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Inventors: Baldi, Alfonso L. (Drexel Hill, PA, US)

Application Number: 404665
Filing Date: 1973-10-09
Publication_date: 1976-04-06
Assignee: Alloy Surfaces Company, Inc. (Wilmington, DE)
Primary Class(es): 428/629 428/653, 428/938
Other Classes:
US Patent Ref:

2490543	Dec, 1949	Robertson	29/196.
2490549	Dec, 1949	Schultz	29/196.
2562118	Jul, 1951	Osdal	148/6.
2917818	Dec, 1959	Themson	117/71.
3248249	Apr, 1966	Collins	148/6.
3248251	Apr, 1966	Allen	106/286.
3284319	Nov, 1966	Hill	148/6.
3618193	Nov, 1971	Anderson	29/195.
3637354	Jan, 1972	Zaremski	29/191.
3713903	Jan, 1973	Zaremski	117/71.

Other Refs:
Primary Examiner: Rutledge, L. Dewayne
Assistant Examiner: Steiner, Arthur J.
Attorney: Connolly and Hutz